EM Spectrum, Origins, and Galaxies

Front

What is a galaxy?

Back

A system of gas, dust, and billions of stars held together by gravity.

Front

What is the lowest point of a wave called?

Back

Trough.

Front

What does red-shift in the spectral lines of light from galaxies imply?

Back

The galaxies are moving farther apart from one another.

Front

Which type of electromagnetic radiation has a wavelength near 10^-5?

Back

Infrared.

Front

What type of galaxy is characterized by a smooth, featureless shape?

Back

Elliptical.

Front

What is the highest point of a wave called?

Back

Crest.

Front

What is the term for the distance between two consecutive crests of a wave?

Back

Wavelength.

Front

What is the measure of the height of a wave from its rest position?

Back

Amplitude.

Front

What type of galaxy has a spiral structure?

Back

Spiral galaxy.

Front

What is the primary force that holds galaxies together?

Back

Gravity.